The present invention relates generally to circuit fabrication and, more particularly, to methods and apparatus for coupling integrated circuit chips and the like to a substrate.
In the fabrication of electrical circuits, it is often desirable to couple a circuit component to a substrate. For instance, one particular example involves the coupling of an integrated circuit chip to a ceramic substrate or to a printed circuit board. Although various techniques exist, adhesives are widely used to couple circuit components to substrates.
Conventional fabrication techniques apply adhesive to the substrate. The circuit components are then placed onto the adhesive on the substrate. One popular and very efficient method for applying adhesive onto a substrate is referred to as a screen printing process. In a screen printing process, a screen that is generally impermeable to adhesive has adhesive placed on it. The screen includes a pattern of holes formed in it, and these holes correspond to desired locations of circuit components on the substrate. When the screen pattern is placed over the substrate, a squeegee moves along the screen and over the holes, so that the adhesive passes through the holes and onto the underlying substrate.
The screen printing process works quite well on substrates that are substantially flat, and it provides a relatively flat adhesive patch that corresponds to the shape of the circuit component to be placed on the substrate. However, the screen printing process does not work well on multi-level substrates or on substrates that include ridges or cavities. On substrates with such surface irregularities, it is difficult for the screen to remain in contact with the substrate as the squeegee passes over the screen. As a result, the adhesive may not be properly transferred from the screen to the substrate.
To deposit adhesive on non-flat substrates, dispensing machines are typically used. Dispensing machines use a plurality of needles to dispense drops of adhesive onto a substrate at the desired locations. Although dispensing machines are able to deposit adhesive on non-flat substrates, such machines unfortunately exhibit various other disadvantages. First, dispensing machines deposit drops of adhesive, rather than carefully formed and relatively flat adhesive patterns such as those produced by screen printing. When circuit components are placed on these drops, the adhesive may not distribute evenly between the component and the substrate. Second, dispensing machines are relatively slow compared to screen printing machines. As is well known, slower techniques tend to limit throughput and increase manufacturing costs. Third, certain very desirable adhesives cannot be dispensed by dispensing machines due to their physical and/or chemical properties.
The present invention may address one or more of the problems discussed above.
Certain aspects commensurate in scope with the originally claimed invention are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
In accordance with one aspect of the present invention, there is provided an apparatus for use in assembling an electronic device. The apparatus includes a fixture that has a substantially regular surface. The substantially regular surface has a plurality of recesses therein. Each of the plurality of recesses are sized to accept a circuit component placed backside up therein such that the backside of the circuit component forms a portion of the substantially regular surface.
In accordance with another aspect of the present invention, there is provided an apparatus for use in assembling an electronic device. The apparatus includes a fixture that has a first surface and a second surface. The first surface has a plurality of holders. Each of the plurality of holders are sized to accept a circuit component placed backside up therein such that the backside of each circuit component is placed in a substantially coplanar relationship.
In accordance with yet another aspect of the present invention, there is provided an apparatus for use in assembling an electronic device. The apparatus includes a first fixture that has a first surface which is substantially regular and that has a plurality of first recesses therein arranged in a given pattern. Each of the plurality of recesses is sized to accept a circuit component placed backside up therein such that the backside of each circuit component is placed in a substantially coplanar relationship. A second fixture has a second surface that is substantially regular and that has a plurality of second recesses therein arranged in a mirror image of the given pattern. The second surface of the second fixture is adapted to mate with the first surface of the first fixture to transfer the plurality of circuit components from the first recesses of the first fixture to the second recesses of the second fixture, wherein each of the plurality of second recesses is sized to accept one of the respective circuit components placed right side up therein.
In accordance with a further aspect of the present invention, there is provided an apparatus for use in assembling an electronic device. The apparatus includes a fixture that has a first surface and a second surface. The first surface is substantially regular and has a plurality of recesses therein. Each of the plurality of recesses is sized to accept a circuit component placed backside up therein such that the backside of each circuit component is placed in a substantially coplanar relationship. A device, such as a screen printer, applies adhesive to the backside of each of the circuit components in the fixture.
In accordance with an even further aspect of the present invention, there is provided an apparatus for use in assembling an electronic device. The apparatus includes: means for holding a plurality of circuit components backside up such that the backside of each circuit component is placed in a substantially coplanar relationship; means for applying adhesive to the backside of each of the circuit components while in the holding means; and means for receiving each of the circuit components from the holding means and supporting the circuit components in a right side up position.
In accordance with a still further aspect of the present invention, there is provided a method of assembling an electronic device. The method includes the acts of: (a) holding a plurality of circuit components backside up such that the backside of each circuit component is placed in a substantially coplanar relationship; (b) applying adhesive to the backside of each of the circuit components; and (c) supporting the circuit components in a right side up position after the adhesive has been applied.
In accordance with a yet further aspect of the present invention, there is provided an apparatus for use in assembling an electronic device. The apparatus includes a first fixture that has a plurality of first holders arranged in a given pattern. Each of the plurality of first holders is configured to hold a circuit component placed backside up therein such that the backside of each circuit component is placed in a substantially coplanar relationship. A second fixture has a plurality of second holders arranged in a mirror image of the given pattern. The second fixture is adapted to mate with the first fixture to transfer the plurality of circuit components from the first holders of the first fixture to the second holders of the second fixture, wherein each of the plurality of second holders is configured to hold one of the respective circuit components placed right side up therein.